Specific Aims: This study will: 1)develop a computer-based decision support system, accessible through the World Wide Web, for women making decisions about the use of preventive hormone therapy (PHT) and related issues, and 2)test the efficacy of this decision support system on women's decisions in randomized controlled trials comparing usual care to usual care plus the computer-based decision support. Background and Significance: As the number of women living to advanced old age increases, interest in PHT to reduce the risk of heart disease and osteoporosis has escalated. Our research has indicated that, for many women, the decision to start PHT is an iterative process involving trading off perceptions of biological benefits and risks with values about the menopause and issues such as "putting foreign substances into one's body." We will develop and evaluate an interactive decision support that will help women to obtain and understand information to make this and related decisions. It will fit the iterative model of decision-making we have found many women use. It will be easily accessible through the World Wide Web and be inexpensive to update as new information appears. Research Design and Methods: The study will take place in 2 phases, a development phase and an efficacy trial phase. In the developmental phase, software for the Comprehensive Health Enhancement Support System (CHESS) will be adapted by the CHESS development team in Madison, WI to run on a webserver and be accessible via the World Wide Web. Seattle investigators will gather scientific information, women's stories, and other resources for women making decisions related to PHT and work with the CHESS team in Madison to incorporate this information into CHESS. Pilot-testing will occur in both sites, with approximately 100 women recruited at each site to help with this process. When the development phase is completed, an efficacy trial will be started in Milwaukee, WI, recruiting 210 women to be randomized to receive either a printed brochure or the brochure and CHESS. 3 months later, a similar efficacy trial will be started in Seattle. At both sites, women will complete an initial survey and follow-up surveys at 3 and 6 months. Analyses will compare the decisions made by women randomized to receive CHESS with those of the control women. Primary outcomes will be measures of decisional quality, including decisional satisfaction and conflict. Adherence to decisions will be measured by survey data at both sites and, in Seattle, pharmacy data on filling of prescriptions for PHT.